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node_modules/matrix-js-sdk/lib/utils/decryptAESSecretStorageItem.js

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+/*
+ * Copyright 2024 The Matrix.org Foundation C.I.C.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { decodeBase64 } from "../base64.js";
+import { deriveKeys } from "./internal/deriveKeys.js";
+/**
+ * Decrypt an AES-encrypted Secret Storage item.
+ *
+ * @param data - the encrypted data, returned by {@link utils/encryptAESSecretStorageItem.default | encryptAESSecretStorageItem}.
+ * @param key - the encryption key to use as an input to the HKDF function which is used to derive the AES key. Must
+ *    be the same as provided to {@link utils/encryptAESSecretStorageItem.default | encryptAESSecretStorageItem}.
+ * @param name - the name of the secret. Also used as an input to the HKDF operation which is used to derive the AES
+ *    key, so again must be the same as provided to {@link utils/encryptAESSecretStorageItem.default | encryptAESSecretStorageItem}.
+ */
+export default async function decryptAESSecretStorageItem(data, key, name) {
+  const [aesKey, hmacKey] = await deriveKeys(key, name);
+  const ciphertext = decodeBase64(data.ciphertext);
+  if (!(await globalThis.crypto.subtle.verify({
+    name: "HMAC"
+  }, hmacKey, decodeBase64(data.mac), ciphertext))) {
+    throw new Error(`Error decrypting secret ${name}: bad MAC`);
+  }
+  const plaintext = await globalThis.crypto.subtle.decrypt({
+    name: "AES-CTR",
+    counter: decodeBase64(data.iv),
+    length: 64
+  }, aesKey, ciphertext);
+  return new TextDecoder().decode(new Uint8Array(plaintext));
+}
+//# sourceMappingURL=decryptAESSecretStorageItem.js.map